1. Field of the Invention
The heating and cooling system is a hydronic unit, air cooled, gas fired, or electric compression, supplying either chilled water or hot water on demand for a variety of residential or commercial applications. The user changes functions by simply changing the settings of a selector switch.
2. Description of the Prior Art
Arkla Industries, Inc. of Little Rock, Ark. manufactures and sells a chiller-heater unit, AY series sold under the Trademark's "ALL-YEAR" and "SERVEL". Such chiller-heater units are also referred to as SERVEL AY Models and are disclosed and described in a four page brochure of Arkla Industries, Inc., Form No. AC 33T-IR-3, dated April 1975. Such a unit which will be specifically described in the application requires that each coil unit of a multiple coil installation be wired to a control center that would be connected electrically to each one of the multiple coils so that should any one coil require heating or cooling it would have the ability to turn on the unit regardless of the demands of the other multiple coils. Thus, the prior art device requires that each one of the multiple coils be wired thermostatically into a central control panel of the chiller-heater unit.
When one of the multiple coil units would be turned on for a cooling mode, the chiller-heater unit would have to be switched into a cooling mode electrically and then would be cycled on the demand of that particular unit. This would allow each and every thermostat in each and every fan and coil unit to control the chiller-heater unit. This, of course, would make a demand on the unit to run on the cooling mode and cycle frequently which would make it very inefficient in operation because of the short cycling; would use considerable energy; and would result in a very costly installation because of the extra control wiring required for wiring the multiple coil units back to the control center. With the AY or chiller-heater unit in a heating mode, the problems are exactly the same. The multiple coil units would be required to snap on and the AY unit would come on through the control center again and cycle on the demand of any one of the multiple coil units.